This is a continuation of copending, commonly assigned International Patent Application No. PCT/EP00/07453, filed Aug. 1, 2000, which is incorporated by reference herein in its entirety. This also claims the benefit of German Patent Application No. 100 10 502.5, filed Mar. 7, 2000, which is also incorporated by reference herein in its entirety.
The invention relates to a mechanical connection of sheet-type panels, as are typically used for a floor covering, such as parquet or laminate flooring, or for ceiling and wall tiling.
In all cases, the individual panels can be joined through a mechanical connection, i.e., interlocking, to form a flat surface, so the panels can be laid without adhesives or additional mechanical fastening elements, such as screws or nails. A particular advantage of this is that the panels can be laid without adhesive bonding, and can therefore be removed.
JP 3-169967 A, on which the present invention is based, describes a mechanical connection of flooring panels. Along one side edge, the panels are provided with a groove, which is formed by an upper lip and a lower lip and extends parallel to the side edge. Embodied on the opposite side edge of the same panel is a tongue, which extends parallel to this side edge. A depression having an interlocking surface that extends at an incline with respect to the top side of the panel is embodied in the groove. A corresponding interlocking element, which has an interlocking surface that extends at an incline with respect to the top side, is embodied at the tongue. Furthermore, fitting surfaces that extend parallel to the top side and serve as abutments for the interlocking surfaces of the groove depression and the interlocking element of the tongue are embodied in the groove and at the tongue, in the region of the respective side edge. In the direction parallel to the top side, the fitting surface of the groove covers the interlocking surface embodied opposite it in the groove. The same applies for the fitting surface and the interlocking surface of the tongue, because the profiles of the groove and the tongue correspond, at least in these sections. In the interlocked state of the connection, the fitting surfaces and the interlocking surfaces fit closely together in pairs in order to keep the upper surfaces of side edges 3 and 4 in contact with one another. Through the cooperation of the fitting surfaces and the interlocking surfaces, the impacting side edges of two panels rest tightly against one another, forming a virtually gap-free connection.
Further mechanical panel connections are known from the prior art disclosed in WO 94/26999, WO 96/27721, WO 97/47834 and WO 98/58142.
A common feature of the mechanical panel connections known from the prior art is that they permit a reliable mechanical interlocking in the direction parallel to the top side of the panels, yet they possess a low rigidity with respect to a rotation of the panels at the adjacent side edges. Hence, the panels can be pivoted relative to one another fairly easily, leading to a loosening of the mechanical connection. In the prior art, this is even desirable to a certain extent for simple panel laying. On the other hand, these known panels in the prior art possess a sufficient rigidity in terms of the aforementioned tilting and pivoting of the panels relative to one another, but the panel interlocking of the connection is inadequately rigid.
The technical problem facing the invention, therefore, is to provide a mechanical connection of panels that is distinguished by improved interlocking and stability properties.
In accordance with the invention, the outlined technical problem is solved by a connection possessing the features of the preamble to claim 1, namely that the groove has fitting surfaces in the region of the groove bottom, the surfaces extending parallel to the top side, and the tongue has fitting surfaces in the region of the end surfaces, the fitting surfaces extending parallel to the top side, with the fitting surfaces resting against one another in the interlocked state of the connection.
In accordance with the invention, it has been recognized that fitting surfaces that stabilize the connection to prevent tilting of the panels toward one another are additionally disposed inside the groove for interlocking the tongue. The interlocking is thus effected by the pair of interlocking surfaces and the pair of fitting surfaces disposed in the region of the side edges and acting as abutments. Therefore, the force generated by the interlocking surfaces effectively prevents the two panels from moving apart in a plane parallel to the top sides and perpendicular to the side edges. The two panels are stabilized to prevent tilting or pivoting along the side edges in the interlocked state by the additional fitting surfaces in the region of the groove bottom or the end surface of the tongue. Thus, different fitting-surface pairs assure the interlocking, on the one hand, and the stabilization of the orientation, on the other hand, of the two panels.
A further advantage of the mechanical panel connection according to the invention is that the two functional groups for interlocking and stabilization of orientation are embodied along a tongue or a groove, so that a desired small panel thickness can be maintained in the region of laminate flooring.
In a preferred embodiment, the distance between the interlocking surface and the fitting surface in the region of the side edges is larger than the distance between the fitting surfaces in the region of the groove bottom or the end surface of the tongue. Consequently, the end of the tongue that first enters the groove at the start of the production of the mechanical connection can be easily received by the groove, because, provided that the two panels are disposed on the same surface, the tongue can penetrate the groove by a predetermined distance without encountering mechanical resistance, so as the panels are joined, the problems arising in the prior art, for example due to the joining and pivoting of the panels relative to one another, do not occur. In addition, the groove tapers from its opening to the groove bottom, or the tongue tapers from the end facing the panel to the end surface, which improves the stability of the side-edge profiles of the two panels.
Additionally, a further surface can be embodied in the groove, the surface extending at an incline with respect to the top side and connecting the depressions of oppositely-located fitting surfaces. Likewise, a surface that extends at an incline with respect to the top side can be embodied on the other side of the groove; this surface connects the interlocking surface to the fitting surface disposed in the region of the groove bottom.
It is further preferable for the end surface of the upper lip and the end surface of the lower lip, which form the groove, to be arranged in essentially one plane. In other words, the two lips extend essentially by the same distance along the side edge, so when the mechanical panel connection is produced, the force required for latching is exerted by an impact block, which rests against the upper lip and the lower lip, and has the largest-possible contact surface. This effectively prevents damage to the side edges.
It is also preferable for the upper and lower lips to be embodied in one piece with the panel. This is possible through the process of milling the profile of the groove or the tongue out of the side edge of the panel, which is advantageous from a manufacturing standpoint. Of course, it is also possible to produce the tongue, the upper lip and/or the lower lip separately and connect them to the panels for attaining the same interlocking and orientation-stabilization properties.